"The active ingredient, dihydroxyacetone, is oxidised when exposed to air, creating a brown colour that is the tan. DHA is extracted from a chemical called glycerol which is taken from sugar-based plants like sugar cane, sugar beet and, more recently, rape seeds."
So it's a nasty long chemical name, that's extracted from another chemical, that comes from a plant. Phew! Well, that's okay then.
A general manager of a spray tan company advises those who are worried about "chemicals" in their spray tan.
"Some spray tans have more than 30 to 40 chemicals in their solutions. Instead, our product comprises only three: DHA 102, natural bronzers and highly purified water."
This is the quantity rather than quality argument of chemical toxicity. More chemicals are obviously more dangerous than fewer (haven't we all seen those mad scientists on late night scifi films - they're surrounded by chemicals!) rather than addressing the specific toxicities of individual chemicals. EoR is also surpised and elightened to learn that "natural bronzers" comprise a single chemical.
The article goes on to mention a side effect or two that some people may experience with DHA: inflammation, irritation, slight to severe rash and extreme itching.
Which means that the "natural" spray tans are safer or better than the "chemical" spray tans in exactly which way? The only difference appears to be in the marketing spin applied to the products.